Surface Area Of Multi-walled Carbon Nanotubes Research Articles

Comprehensive investigation of isotherm, RSM, and ANN modeling of CO2 capture by multi-walled carbon nanotube

Chemical vapor deposition was used to produce multi-walled carbon nanotubes (MWCNTs), which were modified by Fe–Ni/AC catalysts to enhance CO2 adsorption. In this study, a new realm of possibilities and potential advancements in CO2 capture technology is unveiled through the unique combination of cutting-edge modeling techniques and utilization of the recently synthesized Fe–Ni/AC catalyst adsorbent. SEM, BET, and FTIR were used to analyze their structure and morphology. The surface area of MWCNT was found to be 240 m2/g, but after modification, it was reduced to 11 m2/g. The modified MWCNT showed increased adsorption capacity with higher pressure and lower temperature, due to the introduction of new adsorption sites and favorable interactions at lower temperatures. At 25 °C and 10 bar, it reached a maximum adsorption capacity of 424.08 mg/g. The optimal values of the pressure, time, and temperature parameters were achieved at 7 bar, 2646 S and 313 K. The Freundlich and Hill models had the highest correlation with the experimental data. The Second-Order and Fractional Order kinetic models fit the adsorption results well. The adsorption process was found to be exothermic and spontaneous. The modified MWCNT has the potential for efficient gas adsorption in fields like gas storage or separation. The regenerated M-MWCNT adsorbent demonstrated the ability to be reused multiple times for the CO2 adsorption process, as evidenced by the study. In this study, a feed-forward MLP artificial neural network model was created using a back-propagation training approach to predict CO2 adsorption. The most suitable and efficient MLP network structure, selected for optimization, consisted of two hidden layers with 25 and 10 neurons, respectively. This network was trained using the Levenberg–Marquardt backpropagation algorithm. An MLP artificial neural network model was created, with a minimum MSE performance of 0.0004247 and an R2 value of 0.99904, indicating its accuracy. The experiment also utilized the blank spreadsheet design within the framework of response surface methodology to predict CO2 adsorption. The proximity between the Predicted R2 value of 0.8899 and the Adjusted R2 value of 0.9016, with a difference of less than 0.2, indicates a high level of similarity. This suggests that the model is exceptionally reliable in its ability to predict future observations, highlighting its robustness.

Abnormal magnetic behavior of prussian blue analogs modified with multi-walled carbon nanotubes

This work examines the origin of the abnormal magnetism exhibited by CuMnFe–PBAs modified with multi-walled carbon nanotubes (MWCNTs). The system of CuMnFe–PBAs@MWCNTs coexists with both large and small clusters. CuMnFe–PBAs clusters have an average particle size of 28 nm, and some of the smaller particles are adsorbed on the surface of MWCNTs. Surprisingly, the magnitude of magnetization increases linearly with decreasing temperature. When above the Curie temperature, the magnitude of magnetization is significantly greater than that of PBAs without being modified. This phenomenon can be attributed to magnetostatic interactions between ultra-fine magnetic nanoparticles adsorbed on the surface of MWCNTs. Using the Monte Carlo method, we simulated the magnetostatic interaction of cylindrical adsorbed particles, and the simulation results are almost identical to those observed experimentally. The results indicate that 0.089 CuMnFe–PBAs clusters per 1 nm2 can be adsorbed onto the surface area of MWCNTs. We demonstrate that MWCNTs adsorbing magnetic particles exhibit magnetic behavior, and suggest a method for producing ultrafine materials. It also introduces a new method of calculating the adsorption efficiency of carbon nanotubes, offering theoretical guidance for future research on nanomaterials with enhanced adsorption efficiency.

Synergetic Effect on Electrochemical Performance of Activated Carbon - Multiwalled Carbon Nanotubes Supercapacitor using various Electrodes in Aqueous Electrolyte

An Electrical double-layer capacitor (EDLC) has been fabricated with activated carbon (AC) and multi-walled carbon nanotubes (MWCNTs), which in turn were synthesized from Pongamia pinnata fruit shell and its seed oil, respectively. The activated carbon was produced by the chemical activation process at varying carbonization temperatures from 600-900 °C for 5 hours in N2 atmosphere. The obtained activated carbon had a high surface area of 1170 m2 g-1 and a total pore volume of 0.5907 cm3 g-1. The surface area of MWCNTs was 216.1 2 m2 g-1 and the total pore volume was 1.5067 cm3 g-1. The as-prepared AC and MWCNTs were characterized by surface area analysis using Brunner-Emmett-Teller method (BET), X-ray diffraction analysis (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopic analysis, Field emission scanning electron microscopy (FESEM), High-resolution transmission electron microscopy (HR-TEM), Energy-dispersive X-ray spectroscopy (EDAX) and DFT (Density functional theory). The electrochemical performance of AC-MWCNTs (25:75) Stainless steel (SS) electrode and Graphite sheet electrode (GE) were studied by cyclic voltammetry, Galvanostatic charge-discharge and electrochemical impedance spectroscopy using 0.5 M Na2SO4 aqueous electrolyte. It has shown a specific capacitance of 174 Fg-1 and 95.26 Fg-1 respectively, using the three-electrode system at a current density of 1 mA g-1. The AC-MWCNT (25:75) SS electrode has exhibited excellent specific capacitance (CSP) and its Specific energy density and Power density were greater than AC-MWCNT (25:75) GE. The electrochemical performance of AC-MWCNT (25:75) SS electrode was identified as a suitable, low-cost and promising energy storage device for future generations. The present investigation attempts to promote the supercapacitor device in the context of available and future technologies for alternative energy systems with outstanding performance.

Study on the mechanical and electrical properties of twisted CNT yarns fabricated from CNTs with various diameters

The mechanical and electrical properties of multiwalled carbon nanotube (MWCNT) yarns with a wide variety of MWCNT diameters were studied to understand the relationship between the microscopic structures of MWCNTs and the load/charge transport properties of macroscopic MWCNT assemblies. The MWCNT diameters were varied from 14.6 nm to 41.6 nm by varying the amount of catalyst loaded in the synthesis by the chloride-mediated chemical vapor deposition method. We found a drastic change in the tensile behavior of twisted yarns from nonlinear deformation to elastic manner associated with the increases in the tensile strength, Young’s modulus, and electrical conductivity of the twisted MWCNT yarns for smaller-diameter MWCNTs. These improvements are due to the increase in the surface area of MWCNTs in the yarn structure. We also carried out microscopic direct tensile tests on the MWCNTs in a scanning electron microscope to investigate the tensile properties of the individual MWCNTs. The in situ experiments revealed that the obtained high value of the Young’s modulus of the yarn originated from that of the individual MWCNTs.

Preparation and Properties of the Nanocomposites Based on Poly(methyl methacrylate-co-butyl acrylate) and Multiwalled Carbon Nanotube

Nanocomposites, based on multiwalled carbon nanotube (MWCNT) and various acrylic copolymers of poly(methyl methacrylate-co-butyl acrylate)s, were prepared and the effects of the copolymer compositions on the electrical and the dynamic mechanical properties of the nanocomposites investigated. Latices of the acrylic copolymer were prepared by emulsion polymerization, and then mixed with MWCNT dispersed in N-methylpyrrolidone to prepare the nanocomposites. The electrical resistivities of the nanocomposites showed threshold decreases with increasing MWCNT content, due to percolation. The critical MWCNT content (Pc) in the nanocomposites for percolation showed minimum with increasing butyl acrylate content within the poly(methyl methacrylate-co-butyl acrylate). Specifically, the nanocomposites of the acrylic copolymer with a butyl acrylate content of 20-40 wt% showed the lowest Pc value of all the nanocomposites investigated. The nanocomposites showed large increases in the storage moduli in the rubbery plateau region. A decrease in the glass transition temperature (Tg) was observed with the nanocomposites and attributed to the characteristics of the nanocomposites, where the large surface area of MWCNT makes the matrix polymers similar to those of free stand thin film polymers.

Electrocatalytic hydrodehalogenation of pentachlorophenol at palladized multiwalled carbon nanotubes electrode

The palladized multiwalled carbon nanotubes (MWCNTs) electrode was prepared for electrocatalytic hydrodehalogenation (HDH) of pentachlorophenol (PCP). The MWCNTs grew directly on graphite by chemical vapor deposition (CVD), and Pd was loaded on MWCNTs with electrochemical deposition. The MWCNTs and Pd catalyst were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption (BET surface area) and X-ray diffraction (XRD). The diameter and surface area of MWCNTs were 40–60nm and 54m2/g, respectively. The particle size of Pd was about 13nm. Electrocatalytic HDH of PCP by Pd/MWCNTs/graphite electrode was performed in H2SO4 anolyte separated by Nafion membrane H-cell. The complete degradation of 0.15mM PCP was achieved at 180min with the dechlorination efficiency being 96%, and the yield of cyclohexanone was 60% (7.4% current efficiency). Compared with the Pd/graphite electrode, the Pd/MWCNTs/graphite electrode exhibited higher dechlorination efficiency and hydrogenation activity of the carbon–carbon double bond for PCP. The effects of anolyte and potential on HDH, electrode stability were also investigated.